diff --git a/internal/services/cosmos/cosmosdb_account_resource.go b/internal/services/cosmos/cosmosdb_account_resource.go
index 4665d07650f0..f2dae067718e 100644
--- a/internal/services/cosmos/cosmosdb_account_resource.go
+++ b/internal/services/cosmos/cosmosdb_account_resource.go
@@ -529,6 +529,14 @@ func resourceCosmosDbAccount() *pluginsdk.Resource {
 							}, false),
 						},
 
+						// Though `tier` has the default value `Continuous30Days` but `tier` is only for the backup type `Continuous`. So the default value isn't added in the property schema.
+						"tier": {
+							Type:         pluginsdk.TypeString,
+							Optional:     true,
+							Computed:     true,
+							ValidateFunc: validation.StringInSlice(cosmosdb.PossibleValuesForContinuousTier(), false),
+						},
+
 						"interval_in_minutes": {
 							Type:         pluginsdk.TypeInt,
 							Optional:     true,
@@ -1920,13 +1928,25 @@ func expandCosmosdbAccountBackup(input []interface{}, backupHasChange bool, crea
 			return nil, fmt.Errorf("`storage_redundancy` cannot be defined when the `backup.type` is set to %q", cosmosdb.BackupPolicyTypeContinuous)
 		}
 
-		return cosmosdb.ContinuousModeBackupPolicy{}, nil
+		result := cosmosdb.ContinuousModeBackupPolicy{}
+
+		if v := attr["tier"].(string); v != "" {
+			result.ContinuousModeProperties = &cosmosdb.ContinuousModeProperties{
+				Tier: pointer.To(cosmosdb.ContinuousTier(v)),
+			}
+		}
+
+		return result, nil
 
 	case string(cosmosdb.BackupPolicyTypePeriodic):
 		if createMode != "" {
 			return nil, fmt.Errorf("`create_mode` can only be defined when the `backup.type` is set to %q, got %q", cosmosdb.BackupPolicyTypeContinuous, cosmosdb.BackupPolicyTypePeriodic)
 		}
 
+		if v := attr["tier"].(string); v != "" && !backupHasChange {
+			return nil, fmt.Errorf("`tier` can not be set when `type` in `backup` is `Periodic`")
+		}
+
 		// Mirror the behavior of the old SDK...
 		periodicModeBackupPolicy := cosmosdb.PeriodicModeBackupPolicy{
 			PeriodicModeProperties: &cosmosdb.PeriodicModeProperties{
@@ -1953,9 +1973,14 @@ func flattenCosmosdbAccountBackup(input cosmosdb.BackupPolicy) ([]interface{}, e
 
 	switch backupPolicy := input.(type) {
 	case cosmosdb.ContinuousModeBackupPolicy:
+		var tier cosmosdb.ContinuousTier
+		if v := backupPolicy.ContinuousModeProperties; v != nil {
+			tier = pointer.From(v.Tier)
+		}
 		return []interface{}{
 			map[string]interface{}{
 				"type": string(cosmosdb.BackupPolicyTypeContinuous),
+				"tier": string(tier),
 			},
 		}, nil
 
diff --git a/internal/services/cosmos/cosmosdb_account_resource_test.go b/internal/services/cosmos/cosmosdb_account_resource_test.go
index 07778117d1c4..d0e73d01f0e7 100644
--- a/internal/services/cosmos/cosmosdb_account_resource_test.go
+++ b/internal/services/cosmos/cosmosdb_account_resource_test.go
@@ -1069,7 +1069,7 @@ func TestAccCosmosDBAccount_backupPeriodicToContinuous(t *testing.T) {
 		},
 		data.ImportStep(),
 		{
-			Config: r.basicWithBackupContinuous(data, cosmosdb.DatabaseAccountKindGlobalDocumentDB, cosmosdb.DefaultConsistencyLevelEventual),
+			Config: r.basicWithBackupContinuous(data, cosmosdb.DatabaseAccountKindGlobalDocumentDB, cosmosdb.DefaultConsistencyLevelEventual, cosmosdb.ContinuousTierContinuousSevenDays),
 			Check: acceptance.ComposeAggregateTestCheckFunc(
 				check.That(data.ResourceName).ExistsInAzure(r),
 			),
@@ -1084,7 +1084,14 @@ func TestAccCosmosDBAccount_backupContinuous(t *testing.T) {
 
 	data.ResourceTest(t, r, []acceptance.TestStep{
 		{
-			Config: r.basicWithBackupContinuous(data, cosmosdb.DatabaseAccountKindGlobalDocumentDB, cosmosdb.DefaultConsistencyLevelEventual),
+			Config: r.basicWithBackupContinuous(data, cosmosdb.DatabaseAccountKindGlobalDocumentDB, cosmosdb.DefaultConsistencyLevelEventual, cosmosdb.ContinuousTierContinuousSevenDays),
+			Check: acceptance.ComposeAggregateTestCheckFunc(
+				check.That(data.ResourceName).ExistsInAzure(r),
+			),
+		},
+		data.ImportStep(),
+		{
+			Config: r.basicWithBackupContinuous(data, cosmosdb.DatabaseAccountKindGlobalDocumentDB, cosmosdb.DefaultConsistencyLevelEventual, cosmosdb.ContinuousTierContinuousThreeZeroDays),
 			Check: acceptance.ComposeAggregateTestCheckFunc(
 				check.That(data.ResourceName).ExistsInAzure(r),
 			),
@@ -3483,7 +3490,7 @@ resource "azurerm_cosmosdb_account" "test" {
 `, data.RandomInteger, data.Locations.Primary, data.RandomInteger, string(kind), string(consistency))
 }
 
-func (CosmosDBAccountResource) basicWithBackupContinuous(data acceptance.TestData, kind cosmosdb.DatabaseAccountKind, consistency cosmosdb.DefaultConsistencyLevel) string {
+func (CosmosDBAccountResource) basicWithBackupContinuous(data acceptance.TestData, kind cosmosdb.DatabaseAccountKind, consistency cosmosdb.DefaultConsistencyLevel, tier cosmosdb.ContinuousTier) string {
 	return fmt.Sprintf(`
 provider "azurerm" {
   features {}
@@ -3512,9 +3519,10 @@ resource "azurerm_cosmosdb_account" "test" {
 
   backup {
     type = "Continuous"
+    tier = "%s"
   }
 }
-`, data.RandomInteger, data.Locations.Primary, data.RandomInteger, string(kind), string(consistency))
+`, data.RandomInteger, data.Locations.Primary, data.RandomInteger, string(kind), string(consistency), string(tier))
 }
 
 func (CosmosDBAccountResource) basicWithBackupContinuousUpdate(data acceptance.TestData, kind cosmosdb.DatabaseAccountKind, consistency cosmosdb.DefaultConsistencyLevel) string {
diff --git a/website/docs/r/cosmosdb_account.html.markdown b/website/docs/r/cosmosdb_account.html.markdown
index 40ec813ffc8f..3c6c18afa427 100644
--- a/website/docs/r/cosmosdb_account.html.markdown
+++ b/website/docs/r/cosmosdb_account.html.markdown
@@ -245,6 +245,8 @@ A `backup` block supports the following:
 
 ~> **Note:** Migration of `Periodic` to `Continuous` is one-way, changing `Continuous` to `Periodic` forces a new resource to be created.
 
+* `tier` - (Optional) The continuous backup tier. Possible values are `Continuous7Days` and `Continuous30Days`.
+
 * `interval_in_minutes` - (Optional) The interval in minutes between two backups. Possible values are between 60 and 1440. Defaults to `240`.
 
 * `retention_in_hours` - (Optional) The time in hours that each backup is retained. Possible values are between 8 and 720. Defaults to `8`.